


My Strange Addiction

by Green_Eggs_and_Ham_SamIam



Category: Haikyuu!!
Genre: Age Difference, Cockwarming, Creampie, Cunnilingus, Dubious Consent, Dumbification, F/M, Female Ejaculation, Fluff, Incest, Multiple Orgasms, Oral Sex, Sibling Incest, Size Difference, Size Kink, Somno But Not Really, Squirting, Unsafe Sex, Vaginal Fingering, Vaginal Sex, Wet Dream, small age difference
Language: English
Status: Completed
Published: 2021-01-01
Updated: 2021-01-01
Packaged: 2021-03-10 19:08:32
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings, No Archive Warnings Apply
Chapters: 1
Words: 4,361
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/28472145
Author URL: https://archiveofourown.org/users/Green_Eggs_and_Ham_SamIam/pseuds/Green_Eggs_and_Ham_SamIam
Summary: Wakatoshi-nii lets you move in with him now that you're attending University. How will this affect your relationship?
Relationships: Ushijima Wakatoshi & Reader, Ushijima Wakatoshi/Original Female Character(s), Ushijima Wakatoshi/Reader
Kudos: 92





	My Strange Addiction

**Author's Note:**

> Hey, tis I, your Secret Santa. I hope you enjoy it, Felicity.

You were so excited to finally attend Uni with Wakatoshi-nii; he arranged everything with your parents-- you would be moving in with him. He was surprisingly okay with the idea, saying that it would be the safest and most cost-effective option. Your parents brought you to your Nii-san’s apartment to get you settled in before you had to go speak with your school advisor. 

Opening the car door and setting your feet on the ground, you lift yourself from the seat of the car. Standing up, shutting the door behind you, and turning around, you see Toshi-nii making his way towards you from the lawn of the apartment.

“Toshi-nii! I missed you so much.” You exclaim as you run to him, wrapping your arms around his waist and resting your cheek on his broad chest. He wraps his arms around your upper half, a hand on your back and one on the base of your skull, holding you close to him.

“I missed you too, Felicity. You can go inside; I will grab your bags.” He says as he lets you go. 

You smile up at him and nod before making your way into his apartment. As you open the door, you are met with a minimalistic styled interior; there is a small kitchen to the right that connects to the living room on the left. Down the center hallway, you can see three doors; one of them must be your new room. Opening the door at the end of the hallway, you are met with a decently sized bathroom, and Nii-san’s toiletries are placed neatly atop the sink counter. 

Walking out of the bathroom, you take a wild guess on which room could be yours, so you look to your right and turn the knob, stepping through the now-open door. Walking into the room, you’re met with a neatly made bed, volleyball posters, family photos, school books, etc.

_This must be Toshi-nii’s room then,_ you think to yourself. Making your way further into the room to look at the decor, you look at the family photos he has. There are only three: one with all four of you, the next with just you and nii-san, and the last one was your graduation photo. 

“Why on earth would he keep this on his shelf?” You release a breathy chuckle. He never was sentimental, so why now? You ponder this thought as you look at the picture of you, not registering the close figure from behind.  
  


“Because it’s you, and I miss you sometimes.” The low rumble of your nii-san’s voice startles you into flinging your head around, and you see him leaning against the door frame.

“Your room is right across the hall from mine, little one, so why are you in mine?” He asks as he approaches you.

You always forget how much taller Toshi-nii is until you’re right by him and you have to look up to speak with him properly. He’s always called you little one since you’ve always been so much smaller than him. Looking up at your nii-san, you put on an overexaggerated pout and huff.

“I’m not little, nii-san, I’m a big kid now.” You say with a playful tone, nearly using your baby voice. 

He just looks at you for a moment before a small smile creeps its way onto his features. He takes the picture frame from your hands and places it back onto his shelf. He turns you, by your shoulders, to face the door of his room.

“Go look at your room, you have no reason to be in mine.” He says into your ear, breath fanning along the side of your neck sending a chill down your spine. 

You just nod and make your way out of his room. He follows behind, closing the door once you both exit the room.

“I’m gonna grab the last of your stuff, don’t forget to say goodbye to mom and dad.” He reminds you as he walks out the front door. 

You decide to take a quick look at your new room first before you say goodbye. You open the door to reveal your new room. It’s small, but not too much smaller than nii-san’s, and it already has a bed, desk, and bookshelf-- all of the things you’ll need for college. Closing the door to your room you go to say goodbye to your parents.

~~~

After your parents leave, you hop onto the couch and look at your nii-san expectantly- patting the seat next to you as you turn to pull the throw blanket over your body.

“Nii-san, can we watch a movie like old times? I have some time before I need to meet with my advisor. Pleeeeeease Toshi-nii?” You playfully whine to him.

Without saying a word, he softly shakes his head and makes his way over to you on the couch. The weight in the couch shifts under him as he sits next to your much smaller form. His arm rests on the back of the couch cushion behind your head, and you take the signal to cuddle into his side, basking in the warmth that his larger body radiates.

You two have always been extremely close; he’s always been a protective nii-san, and you’ve always been so grateful. Whenever you were scared at night, he would let you crawl into bed with him and sleep there until morning. As you got older, you would end up just sleeping in his room to feel closer to your nii-san. He got _so_ busy in high school, but you couldn’t blame him-- he had a passion, and you weren’t one to get in the way of that. So you would just sleep with him; that was how you both would spend time together. It was different, and others thought it was weird, but for you it was natural.

You started to realize that the way you looked at your nii-san was wrong when you had your first crush at ten. You told your nii-san you thought a boy at school was cute, and he told you that’s what people say when they like someone. You didn’t fully understand because, well, you always thought your nii-san was cute. You thought that was normal though, thought that imouto’s and nii-san’s always loved each other that way.

Once the movie began, you pulled the blanket over the both of you completely and nuzzled into your nii-san’s chest. It had been so long since you last saw him, and you just really needed him, needed to feel him against you again. His arm moved from the back of the couch cushion to your shoulders, holding you closer to him, before he pulled you up into his lap. Your head rests on his pecs, his arms wrapped around your curvy frame, rubbing circles into the exposed skin of your hip with his thumb.

His warm body, the sound of his heartbeat, the steady rise and fall of his chest, and the soft rumble he makes when he finds something funny from the movie... all of it is like a spell to send you into the most peaceful slumber you’ve had since your nii-san’s been away at Uni.

In your dream, you can still feel the warmth from your nii-san’s strong body. You can still feel his skin against yours, but you can feel his lips on more than just your forehead. His calloused hands running along the bare skin of your sides, and his teeth scrape along your soft skin. It’s all quite overwhelming, but it feels so good. You can’t see him in your dream, but you know it’s your Toshi-nii; he feels like none other.

Toshi takes recognition of your dream state: the way you’re clutching onto his shirt, whining into his neck, and rubbing your thighs together in his lap. He’s not stupid- he knows you’re having a wet dream, but of who is the real question. He hates that he becomes jealous at the thought, the mere idea of his imouto crying out someone else’s name while they make her cum... it makes a wave of anger he didn’t understand rise within his chest. He’s always felt this way about you, and he can’t help it-- you’re so perfect, you were basically made for him.

Suddenly, all of his anger is gone at the soft moan you let out of his name. _“Toshi-nii, m-more.”_ The neediness in your tone is enough to make his cock twitch to life beneath you. The way you’re grinding down into his lap is not helping his problem at all, and he’s conflicted on whether or not to stop you. He loves this feeling of you in his lap, whimpering out his name. It’s intoxicating, and he’ll never be able to get enough of you as long as he lives.

He decides that he needs to stop you before he can’t calm himself down and before you wake up. He’s terrified of what you’d think of him if you woke up to him hard beneath you. He adjusts your hips in his lap so that you can’t grind down on him anymore, just long enough for him to once more become flaccid, then he wakes you up. You’re flushed and sweaty from your dream, completely unaware that you came in your sleep, or that your nii-san is the one that made you cum in your dream.

Once the movie is over you get up and change before meeting your advisor for school… and this begins your new life with your nii-san at Uni.

~Two Weeks Later~

You had just asked nii-san for some towels so you could take a shower. He hands you the towels and shows you how to work the shower knob, leaving you to watch his last game in the living room. You take a short shower, just enough to get all the dirt from the day, so far, off. You were really thirsty once you stepped out of the shower, so you decided to take a peek out the door to see if Toshi-nii was still in the living room. He wasn’t, so you decided to scurry into the kitchen to grab a glass of water before you got dressed. While grabbing your glass of water though you don’t hear the opening of nii-san’s bedroom door.

Suddenly, the sound of someone clearing their throat from behind startles you. You whip around to face the sound. Your towel though, doesn’t follow your body falling onto the ground. You’re left entirely bare in front of your nii-san. His eyes go wide at the sight of your naked body, his face begins to flush slightly, and you haven’t yet realized what just happened. You let out a panicked squeal at the realization that you’ve effectively flashed your nii-san. You bend down quickly trying to grab your towel and cover yourself once more, though as you begin to stand back up a large hand is laid on your uncovered back, halting your movements. You don’t know when he got so close to you, but that’s not the point right now, what on earth is he doing?

“N-nii-san, what are you doing?” You ask, voice shaky as your body trembles from the air on your still-damp skin.

He doesn’t say a word as he picks you up and throws you over his shoulder. You don’t struggle, you don’t want to make anything more awkward than it already is, nii-san is probably just gonna take you to your room anyways. When he opens the door to his bedroom you’re extremely confused, more so when you’re dropped onto the bed. You let out a little huff when you hit the mattress. Thankfully, it’s a soft bed, and Toshi-nii wastes no time crawling on top of you. He still hasn’t uttered a single word, part of you is scared. The other part is curious if what you think is happening is what he’s going to do.

When you shift under him, your hip brushes against his hard cock. His breath hitches in his throat, and you take in a sharp breath at the sensation. He’s so big. You wonder if this is why he’s on top of you right now- does he look at you as more than his imouto? Your thoughts come to a screeching halt once he growls from his impatience and slams his lips into your own. You don’t kiss back at first, still in shock, and for the first time ever you think Toshi-nii might actually be scared. The look on his face when he pulls back from you, once he realized you weren’t kissing back, is that of pure panic.

“Felicity, I’m sorry. I shouldn’t have done that.” He apologizes with sincerity swirling in his eyes. 

Part of you wants to say that he should be and that this is wrong, but the other part of you wishes he hadn’t pulled away. Taking a short moment to collect your thoughts, you decide that actions have always spoken louder than words, especially with Toshi-nii. The soft noise of surprise he makes when you pull his face to yours, connecting your lips once more, is nothing compared to the low moan he lets out when he realizes that you’re reciprocating.

The heat that floods your body is overwhelming, to say the least. The feeling of your lips meeting Toshi-nii’s and your tongues quickly tangling together in pure passion is intoxicating. Toshi-nii separates from your lips to hastily tear off his shirt and quickly dive back down to your swollen lips.

The feeling of his hard, warm chest against your own sends a soft chill down your spine. Nii-san feels like no one you’ve ever felt before, he feels perfect against your body like this. His hands move to cup your breasts, pinching your already-hard nipples between calloused fingers. He begins to roll his hips against your own, groaning into your mouth at the craved friction. He separates from your lips to plant sloppy open mouth kisses on the expanse of your neck; he revels in the moans you release when he finds your sweet spot.

He begins to trail his kisses down the valley of your breasts, nearing your navel. He makes his way to your hips, instead of dipping into your center he trails his kisses along your inner thighs, his lips so close to your lower ones. He moves to the opposite thigh kissing up towards your already dripping core. His eyes flicker up to meet your pleading ones, and that’s all he needs to dive into your sensitive little cunny. His tongue lays flat as he licks a long slow stripe from your dripping hole to your sensitive little bud.

Your hand shoots out to grab his hair as you let out a shaky moan, the groan he lets out into your folds has you quivering beneath him already. He holds you down by wrapping his right arm under your leg to press against your hips that you didn’t even realize were bucking up into his mouth for more. He places his tongue flat against your clit, applying light pressure while circling around your bud. The pleasure he’s giving you is alarming. It feels so good, and all you want is to cum all over his tongue.

It doesn’t take too long for you to start feeling the pleasure building within you; it goes even faster once he swipes his left-hand digit along your soaking hole. The way his finger slides into you so effortlessly is a tell of how good he’s making you feel. He slips a second finger alongside the first and slowly curls them upwards, dragging the tips of his thick fingers along your g-spot. The feeling makes you moan as your thighs clench around his skull, and he moans out at the feeling of your thighs wrapped around his head and the way you tighten around his fingers when he hits your spot perfectly. He continues to rub your g-spot while still lapping over your clit. Your pleasure is escalating, hurdling you over the edge of mind-numbing bliss. 

Your body locks up as you approach your peak, and Toshi-nii keeps up his pace, making sure you get your release. Suddenly your body contorts, toes curling, back arching, and a hand clutching the sheets as well as your nii-san’s hair. He keeps going, wanting you to ride out your orgasm on his fingers and tongue, only stopping once you begin frantically twitching in overstimulation. 

He pulls away from your abused little hole, mouth and chin glistening with your juices and his saliva. He pulls his long, thick, calloused digits from you, bringing them to his lips and sucking off all of your arousal. He moans at the taste of your cum, pupils blown wide when his lidded eyes meet your own. You’re caught off guard when he dives into your hole once more, desperate for more of your cum in his mouth, licking and slurping away at the ethereal taste of your arousal. Once he’s had his fill, he removes himself with a pop.

“Fuck, Felicity, you taste amazing; I can’t get enough of it.” He breaths out looking in your eyes then shifting his gaze to your cunt once more. His fingers push your labia apart, showing him your clenching hole and throbbing bud.

“Look at this perfect little cunny, so puffy and pink. _Fuck_ , you have the prettiest cunny I’ve ever seen. Little one, you’re _never_ gonna be the same once you take _my_ cock- I’m gonna stretch this cunny open on my massive cock.” He growls out at you, eyes finally flicking upwards to meet your own that plead for him to take you as his own. 

This is what you’ve always wanted- you always thought Toshi-nii was so handsome, but you knew it was wrong, so you never did a thing about it. Now you’re here, on his bed, about to be absolutely destroyed by his massive length.

As he stands at the foot of the bed, he removes his pants and boxers, crawling atop you to cage you between his large, muscular arms. His eyes search your face for any signs of discomfort, uncertainty, or even regret; seeing nothing other than your blissful afterglow, he’s reassured of his next decision. Pressing a soft yet passionate kiss to your lips, he guides his tip along with your dripping slit coating himself in your cum. Slicked up and throbbing, his hard cockhead presses at your entrance. He pauses to pull back and look you in the eyes once more.  
  


“Are you sure?”

“Please, nii-san, need you inside me.”

“I love you, Felicity.” He breathes, pushing his length into your awaiting entrance. 

Even with your previous orgasm, the stretch of even just the head of his cock is somewhat uncomfortable. He’s so big- if you can barely handle the tip, how are you supposed to take all of him?  
  


“It’ll fit- I’ll be gentle, and I’ll make it fit.” He says, reading your expression perfectly, laying a soft peck to your forehead. 

He continues to slowly ease his girth inside of your tight hole, groaning at the way your cunny is gripping him so tightly, trying to pull him deeper inside of you. You’re moaning out, unabashed, completely overtaken by the feeling of being fuller than you ever thought possible, and he’s not even halfway.

“S-so fu- full. So- so good, _fuck_ , more p-please, _need mo- more_!” You moan loud, voice cracking as your request is met with the constant drag of his cock against your g-spot. 

Toshi-nii is halfway in now, but he stopped moving. He had to stop because of the way you began clamping down on his throbbing cock. You’re cumming already, just from him being halfway inside of you, and it’s testing his restraint in the best way. The feeling of you cumming around half of his cock, along with the beautiful expressions you make, feel like ecstasy to him. The way your body is arching, eyes rolling into the back of their sockets, toes curling, fistfuls of sheets, all of it is Toshi-nii’s drug. He’s addicted to you, your body, the way his name leaves your lips in breathless pants and pleads as he sends you into mind-numbing pleasure.

As your second orgasm of the night passes, he begins to push in once more, cooing at the whimpers of light overstimulation you let out. He continues to push further into your tight, wet heat, his hands balled into fists, knuckles bone-white as he tries so hard not to just slam all the way into you. You’re intoxicating, taking him so well already. No one has ever been able to take even three-quarters of his length before, yet you’re taking it so well.

The thought that you’ve been with someone of similar size pops into his mind briefly, but is soon pushed away at the sight of your tear-stained face. He hesitates slightly for just a moment before he realizes you’re crying from the pleasure, your bottom lip pulled taut between your teeth, trying to suppress your moans. His thumb comes up to pull your lip from your teeth, pressing his lips to yours savoring your taste. Pulling back from your lips, he looks into your eyes, pupils wide, lidded with lust, just admiring you.

“Don’t hide those pretty little moans from me, imouto. I wanna _hear_ you fall apart on my cock.” He growls out, licking a stripe from your collar bone to just below your ear.

Following the instructions of your nii-san, you let your moans slip freely from your lips as he continues to shove the rest of his cock into your greedy hole. You’re squeezing him so well- your pussy is nearly sucking him inside of you- and it just feels too good to handle. The way that his fat cock rests inside of you once he’s fully inside is intoxicating, it pulls a guttural moan from the both of you. The way that his cock dragged against your g-spot for so long once again makes you cum around him, this one twice as powerful as the last. 

The way your back arches into Toshi-nii’s chest, your eyes roll back into your head, and your walls spasming around his entire cock makes him go feral. He can’t handle how good you feel- no one has ever been able to take this much of him, but you’re taking him so well. You were made to take your nii-san’s cock, the head of his cock just perfectly kisses your cervix. The feeling of being fuller than you ever thought possible makes your head spin, nails digging into his tan flesh at the overwhelming orgasm that still wracks through your body.

“F-full _so_ full. So g-good.”

“You’re so t-tight, _fuck_. You take me so w-well.”

“Please _please_ , move, I _need_ you, need you so bad.”

His hips roll against yours before slowly dragging his cock from your velvety walls. Just the tip remains inside of you until he slams into you, making you cry out. He groans at the feeling of sheathing himself inside you so quickly- he can’t get enough. He will always need more of you.

He begins a brutal pace, his cock hits every spot inside you- even spots you didn’t know existed. You’re just a babbling mess at this point- you can’t think after all the orgasms you’ve had. You lost count at the sixth orgasm, but you know it has to have at least doubled by now. You’re nothing more than a twitching hole to be used at this point, and you love it so much.

You can tell your nii-san is getting close, and the way his lips begin to hastily attach to the flesh of your neck, leaving fresh hickeys in his wake. His pants and grunts become more frequent in your ear and against your skin. His hand goes between your bodies, large digits finding your clit rubbing tight circles. The extra stimulation brings a new feeling to your lower tummy, and a new wave of heat rushes through your body, overwhelming you completely. A new and foreign coil begins to tighten in your stomach, making your body tense and twitch.

“Cum with me, Felicity- want you to cum on my twitching cock. I want you to milk this cock you love so much.”

Those words are the last thing you need to fly over the edge, pulling Toshi-nii with you. The feeling of his cock slamming into your g-spot and cervix combined with the way he plays with your clit was too much already. The feeling of his cock twitching inside of you shooting his hot white load into your pretty little cunny makes you see stars. The orgasm that wracks your body is like none you’ve ever had before- your back arches hard off the bed, and your legs shake violently- you feel like you’re exploding everywhere.

Coming down from your blinding high, you take note of the wetness covering your lower body. Toshi-nii made you squirt. No one has ever been able to make you squirt before, and it felt amazing. You can feel his cock begin to soften inside of you as he begins to pull out. You quickly wrap your legs around his lower back, pulling him back in as much as possible. The hiss he lets out at you pulling him in once more makes you clench around his half-hard cock.

“P-please, can we stay like this just a little longer, nii-san?” You ask, voice soft, as a blush creeps across your face. He hums softly, and, seeing the bashful expression on your face, he brushes a brown strand of hair behind your ear.  
  


“Of course, Felicity, anything for you.” He scoops you up with an arm to pull you into his chest as he lays down on his back, you resting on his warm chest.

He plays with your hair as you listen to his heartbeat. This moment is so pure, so perfect. You never want it to end, and as long as no one finds out, it never will.


End file.
